1. Field of the Invention
This invention relates to a boom stabilizer for an underground mining machine and more particularly to a stabilizing plate pivotally mounted on the boom of a mining machine and operable to be raised to a preselected position to abut the mine roof when the material dislodging apparatus is positioned adjacent the mine roof for sumping into the mine face to prevent the cutting elements from engaging the mine roof.
2. Description of the Prior Art
Mining machines, for example as illustrated in U.S. Pat. No. 3,730,593, are utilized in underground mining operations to continuously dislodge solid mineral material from the face of the mine shaft. Generally, a boom member extends forwardly from an elongated body portion of the mining machine that is propelled through the mine on endless crawler tracks. The boom member is pivotally connected to the mining machine body portion and rotatably supports a material dislodging apparatus, such as a drum member having peripherally extending cutting elements. The drum member extends transversely to the longitudinal axis of the body portion and upon rotation the cutting elements dislodge solid material from the mine face. The drum member is raised to a preselected vertical height in the mine as determined by the thickness of the mineral vein. The drum member is rotated and sumped into the mine face with the drum member positioned adjacent the mine roof. Once the drum member has advanced into the mine face, the boom member is pivoted downwardly to move the drum member vertically downwardly through the face to make a shear cut in the face. The dislodged material is gathered by a gathering device which moves the dislodged material rearwardly onto a conveyor that extends longitudinally on the mining machine to transport material toward the rear of the mining machine.
In conducting the downward shear cut by the drum it is desired to maintain the peripheral cutting edge of the cutting elements disengaged from the mine roof so that the elements cut only the vertical mine face. Positioning the cutting elements in cutting relation with the mine roof and the mine face increases the load upon the motors that rotate the drum member when the drum member is sumped forwardly into the mine face adjacent the roof. Furthermore, if the drum member is permitted to dislodge material from the mine roof during the sumping operation an irregular roof surface results. An irregular roof surface presents considerable difficulty in the installation of mine roof bolts and other roof support apparatus.
The drum member has a tendency when raised to the vertical position adjacent the mine roof for the sumping operation to move upwardly or climb the mine face into the roof as the drum member is sumped inwardly. If the cutter elements engage both the mine roof and face during the sumping operation, an additional load is placed on the drum motors that may result in damage to the motors.
There is need in the operation of an underground mining machine to prevent cutting engagement of the material dislodging apparatus with the mine roof during the sumping operation adjacent the mine roof. The cutting elements of the material dislodging apparatus should be placed from cutting engagement with the mine roof and the material dislodging apparatus should be prevented from climbing upwardly into the roof during the sumping operation. Furthermore, there is need to prevent vertical movement of the material dislodging apparatus beyond a preselected vertical height during the sumping operation and thereby form a mine roof of a substantially uniform height and free of undulations.